Lithium-containing materials

Abstract

A lithium-containing material is provided. [Solution] The present invention relates to a lithium-containing material in the form of white powder, the components of the lithium-containing material include lithium (Li), aluminum (Al), phosphorus (P), fluorine (F) and oxygen (O), and the content ratio of each element according to mass ratio is as follows: the content of element lithium is more than 0% and not more than 12%, the content of element aluminum is 5%-40%, the content of element phosphorus is 1%-35%, the content of element fluorine is 0.4%-22%, and the content of element oxygen is 2%-34%, and the lithium-containing material is used as an electrode additive or diaphragm coating material for lithium-ion batteries.

Description

[Technical Field]

[0001] (cross reference) This application claims priority to a Chinese patent application filed with the China Patent Office on August 19, 2021, bearing application number 202110956905.6 and entitled "Lithium-containing material."

[0002] (Technical field) The present invention relates to the technical field of materials, and in particular to lithium-containing materials. [Background technology]

[0003] With the widespread application and rapid development of lithium batteries, people's performance requirements for lithium-ion batteries are increasing. Lithium batteries are required not only to have high capacity, but also to maintain good capacity retention during repeated charging and discharging, exhibit good cycle characteristics, long service life, and high safety performance.

[0004] To extend the life of a battery, two factors are usually considered: first, to improve the structural stability of the positive electrode, negative electrode, diaphragm, and electrolyte material to prevent structural changes during multiple cycles; and second, to consider the external and usage conditions of the battery.

[0005] However, there are limitations to improving the battery's service life due to the external and operating conditions of the battery, and only by improving the performance of the materials that determine the "battery's genes" inside the battery can the cycle characteristics of the battery be fundamentally improved. In order to extend the service life of lithium batteries, new lithium-containing materials are used to improve the cycle characteristics of lithium batteries, which in turn can extend the service life of the battery. Summary of the Invention [Problem to be solved by the invention]

[0006] The embodiments of the present invention provide a lithium-containing material that has good electrolyte wettability and good lithium ion conductivity, can sufficiently suppress lithium dendrites, and can improve the service life and cycle characteristics of lithium batteries. [Means for solving the problem]

[0007] An embodiment of the present invention provides a lithium-containing material in the form of white powder, the lithium-containing material comprising lithium (Li), aluminum (Al), phosphorus (P), fluorine (F), and oxygen (O), wherein the mass ratio of each element is as follows: the content of element lithium is greater than 0% and less than 12%, the content of element aluminum is 5% to 40%, the content of element phosphorus is 1% to 35%, the content of element fluorine is 0.4% to 22%, and the content of element oxygen is 2% to 34%; The lithium-containing material is used as an electrode additive or a diaphragm coating material in lithium-ion batteries.

[0008] Preferably, the X-ray diffraction XRD pattern of the lithium-containing material has characteristic diffraction peaks at 2θ angles of 28°, 30° and 19°.

[0009] Preferably, the tap density of the lithium-containing material is 0.60 to 1.48 g / cm 3 is.

[0010] Preferably, the solubility of the lithium-containing material in water, ethanol, N-methyl-2-pyrrolidone NMP is less than 1 g / 100 g.

[0011] Preferably, the total content of magnetic impurities in the lithium-containing material is less than 1.5 ppm, and the magnetic impurities include one or more of Cr, Fe, Ni, Zn, and Co.

[0012] More preferably, the lithium-containing material has a Cr content≦0.15 ppm, an Fe content≦1.35 ppm, an Ni content≦0.04 ppm, an Zn content≦0.01 ppm, and a Co content≦0.01 ppm.

[0013] Preferably, the lithium-containing material is further doped with an element M, the content of the element M in the lithium-containing material is 0% to 30%, and the M is selected from any one of H, K, Cl, and Na.

[0014] Preferably, the general chemical formula of the lithium-containing material is Li 1+x M 1-x Al(PO4)O 1-y F 2y where 0≦x≦1, 0 <y<0.1である。 [Effects of the Invention]

[0015] The lithium-containing material according to the embodiment of the present invention has good electrolyte wettability and good lithium ion conductivity, can sufficiently suppress lithium dendrites, and can improve the service life and cycle characteristics of lithium batteries. [Brief explanation of the drawings]

[0016] Hereinafter, the technical solutions in the embodiments of the present invention will be described in more detail with reference to the drawings and examples.

[0017] [Figure 1] 1 is an X-ray diffraction (XRD) pattern of a lithium-containing material according to an example of the present invention. [Figure 2] 1 is a schematic diagram illustrating the principle of contact angle measurement according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0018] Hereinafter, the present invention will be further described with reference to the drawings and specific examples. However, it should be understood that these examples are merely for the purpose of explaining the present invention in more detail and are not intended to limit the present invention in any way, i.e., they are not intended to limit the protection scope of the present invention.

[0019] The lithium-containing material according to the embodiment of the present invention is in the form of a white powder, and the components of the lithium-containing material include lithium (Li), aluminum (Al), phosphorus (P), fluorine (F), and oxygen (O), where, according to mass ratio, the content ratio of each element is as follows: the content of element lithium is more than 0% but not more than 12%, the content of element aluminum is 5% to 40%, the content of element phosphorus is 1% to 35%, the content of element fluorine is 0.4% to 22%, and the content of element oxygen is 2% to 34%.

[0020] In a preferred embodiment, the lithium-containing material is further doped with element M, the content of element M in the lithium-containing material is 0% to 30%, and M is selected from any one of H, K, Cl, and Na.

[0021] Preferably, the general chemical formula of the lithium-containing material is Li 1+x M 1-x Al(PO4)O 1-y F 2y where 0≦x≦1, 0 <y<0.1である。

[0022] The X-ray diffraction XRD pattern of the lithium-containing material according to the present invention has relatively clear and characteristic diffraction peaks at 2θ angles of 28°, 30° and 19°.

[0023] The tap density of the lithium-containing material according to the present invention is 0.60 to 1.48 g / cm 3 is.

[0024] The solubility of the lithium-containing material according to the present invention in water, ethanol, N-methyl-2-pyrrolidone NMP is less than 1 g / 100 g.

[0025] The total content of magnetic impurities in the lithium-containing material according to the present invention is less than 1.5 ppm, and the magnetic impurities include one or more of Cr, Fe, Ni, Zn, and Co. Specifically, the Cr content is ≦0.15 ppm, the Fe content is ≦1.35 ppm, the Ni content is ≦0.04 ppm, the Zn content is ≦0.01 ppm, and the Co content is ≦0.01 ppm.

[0026] The lithium-containing material according to the present invention can be used as an electrode additive or diaphragm coating material for lithium ion batteries, and the material has good electrolyte wettability and good lithium ion conductivity, can sufficiently inhibit lithium dendrites, and can improve the service life and cycle characteristics of lithium batteries.

[0027] Example 1 Regarding the lithium-containing material of this example, as can be seen from the appearance, the material is a white powder, and the general chemical formula of the lithium-containing material is Li 1+x M 1-x Al(PO4)O 1-y F 2y where the element M is not included and the chemical formula is Li2Al(PO4)O 0.94 F 0.12 According to the mass ratio, the composition and content of the elements are as follows: the lithium content is about 8.6%, the aluminum content is 35%, the phosphorus content is 28%, the fluorine content is about 16%, and the oxygen content is about 12.4%.

[0028] The XRD pattern of the material was found to have clear characteristic diffraction peaks at 2θ angles of 28°, 30°, and 19°, as shown in Figure 1. Testing revealed that the tap density of the material was 1.08 g / cm 3 is.

[0029] ICP analysis of the material showed that the elemental lithium content was 8.45%, the elemental aluminum content was 34.7%, the Cr content was 0.1298 ppm, the Fe content was 1.2052 ppm, the Ni content was 0.0276 ppm, the Zr content was 0 ppm, the Co content was 0.0006 ppm, and the total magnetic impurities content was 1.3632 ppm.

[0030] The ternary cathode material NCM622, carbon black, polyvinylidene fluoride, and the above lithium-containing material were uniformly mixed in a mass ratio of 8:1:0.5:0.5 and coated on an aluminum foil current collector to form the battery's cathode. Graphite was used as the anode, a single-layer polyethylene film as the diaphragm, and a 1 M LiClO4 solution in ethyl acetate as the electrolyte. The button battery was assembled in an argon-filled glove box.

[0031] Example 2 A ternary cathode material NCM622, carbon black, and polyvinylidene fluoride were uniformly mixed in a mass ratio of 8:1:1 and applied to an aluminum foil current collector to form the positive electrode of the battery. Graphite and the lithium-containing material from Example 1 were uniformly mixed in a mass ratio of 9:1 and applied to copper foil to form the negative electrode of the battery. A single-layer polyethylene film was used as the diaphragm, and a 1 M LiClO4 solution in ethyl acetate was used as the electrolyte. The battery was assembled into a button cell in an argon-filled glove box.

[0032] Example 3 A ternary cathode material NCM622, carbon black, and polyvinylidene fluoride were uniformly mixed in a mass ratio of 8:1:1 and coated on an aluminum foil current collector to form the battery's cathode. Graphite was used as the anode, and the lithium-containing material from Example 1 was coated on a single-layer polyethylene film to form the diaphragm. A 1 M LiClO4 solution in ethyl acetate was used as the electrolyte. The battery was assembled in an argon-filled glove box.

[0033] Example 4 Regarding the lithium-containing material of this example, as can be seen from the appearance, the material is a white powder, and the general chemical formula of the lithium-containing material is Li 1+x M 1-x Al(PO4)O 1-y F 2y where the element M is not included and the chemical formula is Li2Al(PO4)O 0.95 F 0.1 According to the mass ratio, the composition and content of the elements are as follows: the lithium content is about 10%, the aluminum content is 38%, the phosphorus content is 26%, the fluorine content is about 20%, and the oxygen content is about 6%.

[0034] When tested, the tap density of the material was 0.84 g / cm 3 is.

[0035] ICP analysis of the material showed that the elemental lithium content was 10.1%, the elemental aluminum content was 37.6%, the Cr content was 0.0326 ppm, the Fe content was 0.3957 ppm, the Ni content was 0.0306 ppm, the Zr content was 0.0053 ppm, the Co content was 0.0002 ppm, and the total magnetic impurities content was 0.4644 ppm.

[0036] The ternary cathode material NCM622, carbon black, polyvinylidene fluoride, and the above lithium-containing material were uniformly mixed in a mass ratio of 8:1:0.5:0.5 and coated on an aluminum foil current collector to form the battery's cathode. Graphite was used as the anode, a single-layer polyethylene film as the diaphragm, and a 1 M LiClO4 solution in ethyl acetate as the electrolyte. The button battery was assembled in an argon-filled glove box.

[0037] Example 5 A ternary cathode material NCM622, carbon black, and polyvinylidene fluoride were uniformly mixed in a mass ratio of 8:1:1 and applied to an aluminum foil current collector to form the positive electrode of the battery. Graphite and the lithium-containing material from Example 4 were uniformly mixed in a mass ratio of 9:1 and applied to copper foil to form the negative electrode of the battery. A single-layer polyethylene film was used as the diaphragm, and a 1 M LiClO4 solution in ethyl acetate was used as the electrolyte. The battery was assembled into a button cell in an argon-filled glove box.

[0038] Example 6 A ternary cathode material NCM622, carbon black, and polyvinylidene fluoride were uniformly mixed in a mass ratio of 8:1:1 and coated on an aluminum foil current collector to form the battery's cathode. Graphite was used as the anode, and the lithium-containing material from Example 4 was coated on a single-layer polyethylene film to form the diaphragm. A 1 M LiClO solution in ethyl acetate was used as the electrolyte. The battery was assembled in an argon-filled glove box.

[0039] Example 7 Regarding the lithium-containing material of this example, as can be seen from the appearance, the material is a white powder, and the general chemical formula of the lithium-containing material is Li 1+x M 1-x Al(PO4)O 1-y F 2y where M is preferably the element hydrogen (H) and has the chemical formula LiHAl(PO4)O 0.96 F 0.08 The mass ratio of the elemental composition and content is as follows: lithium content is about 4.7%, aluminum content is 35.6%, phosphorus content is 24.7%, fluorine content is about 18.5%, oxygen content is about 5.3%, and hydrogen content is about 1.68%. The XRD pattern of the material, as shown in Figure 1, has obvious characteristic diffraction peaks at 2θ angles of 28°, 30°, and 19°.

[0040] When tested, the tap density of the material was 1.08 g / cm 3 is.

[0041] ICP analysis of the material showed that the elemental lithium content was 8.45%, the elemental aluminum content was 34.7%, the Cr content was 0.1298 ppm, the Fe content was 1.2052 ppm, the Ni content was 0.0276 ppm, the Zr content was 0 ppm, the Co content was 0.0006 ppm, and the total magnetic impurities content was 1.3632 ppm.

[0042] The ternary cathode material NCM622, carbon black, polyvinylidene fluoride, and the above lithium-containing material were uniformly mixed in a mass ratio of 8:1:0.5:0.5 and coated on an aluminum foil current collector to form the battery's cathode. Graphite was used as the anode, a single-layer polyethylene film as the diaphragm, and a 1 M LiClO4 solution in ethyl acetate as the electrolyte. The button battery was assembled in an argon-filled glove box.

[0043] Example 8 A ternary cathode material NCM622, carbon black, and polyvinylidene fluoride were uniformly mixed in a mass ratio of 8:1:1 and applied to an aluminum foil current collector to form the positive electrode of the battery. Graphite and the lithium-containing material from Example 7 were uniformly mixed in a mass ratio of 9:1 and applied to copper foil to form the negative electrode of the battery. A single-layer polyethylene film was used as the diaphragm, and a 1 M LiClO4 solution in ethyl acetate was used as the electrolyte. The battery was assembled into a button cell in an argon-filled glove box.

[0044] Example 9 A ternary cathode material NCM622, carbon black, and polyvinylidene fluoride were uniformly mixed in a mass ratio of 8:1:1 and coated on an aluminum foil current collector to form the battery's cathode. Graphite was used as the anode, and the lithium-containing material from Example 7 was coated on a single-layer polyethylene film to form the diaphragm. A 1 M LiClO solution in ethyl acetate was used as the electrolyte. The battery was assembled in an argon-filled glove box.

[0045] (Comparative Example) A ternary cathode material NCM622, carbon black, and polyvinylidene fluoride were uniformly mixed in a mass ratio of 8:1:1 and coated on an aluminum foil current collector to form the battery's cathode. Graphite was used as the anode, a single-layer polyethylene film as the diaphragm, and a 1 M LiClO4 solution in ethyl acetate as the electrolyte. The battery was assembled into a button cell in an argon-filled glove box.

[0046] In the battery performance test, the button batteries manufactured in Examples 1 to 9 and Comparative Example were tested to measure the discharge capacity at different rates of 1 C to 10 C, the self-discharge performance K value after 7 and 15 days of storage, and the temperature rise at the center of the battery surface when discharged at different rates within a charge-discharge voltage window of 1 V to 2.5 V. At the same time, the specific capacity was also tested for the first time and after 100 charge-discharge cycles. The test results are shown in Table 1.

[0047] [Table 1]

[0048] Based on the values ​​in Table 1, the capacity retention rates at 5C / 1C, 10C / 1C and 100 cycles were calculated and are shown in Table 2 below.

[0049] [Table 2]

[0050] As can be seen from the data, the 5C / 1C rate characteristics and 10C / 1C rate characteristics of Examples 1 to 9 are both higher than those of the Comparative Example, and the capacity retention rate after 100 cycles is also significantly higher than that of the Comparative Example. When discharged at different rates, the temperature rise increases as the discharge rate increases, and at the same rate, the temperature rise of the Comparative Example is higher than that of Examples 1 to 9. Furthermore, when the storage time is the same, the self-discharge performance K values ​​of the Examples are significantly smaller than that of the Comparative Example.

[0051] As can be seen from the data in Table 1, the specific capacity and first cycle performance of the button batteries manufactured by adding the lithium-containing material in Examples 1 to 9 of the present application are significantly better than those of the comparative examples. It is believed that the addition of the lithium-containing material increases the number of lithium ions during charging and discharging, providing sufficient lithium ions for the formation of an SEI film, and thus improving the first cycle performance and specific capacity.

[0052] During the discharge process of a lithium-ion battery, lithium flakes are dissolved into lithium ions, and during the charge process, the lithium ions are reduced to metallic lithium. During this reduction process, due to thermodynamic reasons, lithium precipitates unevenly, resulting in the formation of lithium dendrites. Previous research has shown that, on the one hand, lithium dendrites can become "dead lithium," resulting in irreversible capacity loss and affecting discharge efficiency. On the other hand, lithium dendrites can also pose serious safety risks, such as diaphragm perforation, short circuiting, and battery explosion. As can be seen from the data in Tables 1 and 2, regardless of whether the lithium-containing material was added to the positive electrode, negative electrode, or diaphragm, the button batteries manufactured with the lithium-containing material had significantly higher rate discharge capacities than the comparative example, and the capacity retention after 100 cycles was also relatively high, at over 85%. In the comparative example, the capacity retention after the same number of discharge cycles was relatively low, at less than 75%, compared to batteries manufactured without the lithium-containing material. Based on the test data, a uniform and stable solid-liquid interface is formed between the electrode material prepared by adding the lithium-containing material of the present invention as an additive and the electrolyte, inducing uniform deposition of metallic lithium. This interface is presumably involved in the reduction of lithium in the lithium-containing material. This suppresses the formation of lithium dendrites and reduces the occurrence of "dead lithium," thereby reducing battery capacity loss and ultimately achieving a high battery rate discharge capacity. Furthermore, based on the temperature rise data at the center of the battery surface measured during discharge at different rates in Table 1, the temperature rise of the battery containing the lithium-containing material of the present invention was more than half that of the comparative battery at the same rate. The reduced operating temperature significantly improved battery safety and avoided high-temperature hazards.

[0053] Furthermore, the quality of the wetting between the electrolyte and the positive electrode, negative electrode, and diaphragm affects the lithium ion migration between the positive and negative electrodes and the battery's interfacial resistance, which in turn affects the battery's discharge rate, discharge capacity, and operating voltage. Therefore, good wetting of electrode materials is beneficial for improving battery performance. The diaphragms prepared in Example 6 and Comparative Example were tested. The negative electrode prepared in Example 5 by blending graphite and a lithium-containing material and the graphite negative electrode in Comparative Example were tested. The positive electrode prepared in Example 4 by blending the ternary cathode material NCM622, carbon black, polyvinylidene fluoride, and a lithium-containing material and the positive electrode without the lithium-containing material in Comparative Example were tested. Figure 2 shows the principle of contact angle measurement. In this example, the same electrolyte solution is dropped onto a diaphragm, a positive electrode, a negative electrode manufactured by adding a lithium-containing material, and a diaphragm, a positive electrode, and a negative electrode manufactured by not adding a lithium-containing material, and the contact angles between the electrolyte solution and the diaphragm, the positive electrode, and the negative electrode are measured using a contact angle measuring device, and the effects of adding a lithium-containing material on the wettability of the battery material are compared.

[0054] [Table 3]

[0055] By comparing the magnitude of the measured contact angles, it was found that the electrode pieces or diaphragms prepared with the addition of lithium-containing materials had smaller contact angles with the electrolyte, and the smaller the contact angle, the better the wettability of the material. Test results showed that the addition of lithium-containing materials to the same prepared electrolyte improved the wettability of the material. Therefore, the lithium-containing materials have good wettability.

[0056] In order to detect the influence of lithium-containing material on the resistivity of positive electrode pieces and negative electrode pieces, obtain the positive electrode pieces in Example 4 and the negative electrode pieces in Example 5, respectively, and use a tester to measure the resistivity of the positive electrode pieces and negative electrode pieces in Comparative Example, and the results are shown in Table 4.

[0057] [Table 4]

[0058] As can be seen from the measurement data in Table 4, the resistivity of the positive and negative electrodes prepared by adding lithium-containing materials is significantly lower than that of the positive and negative electrodes prepared by not adding lithium-containing materials in the comparative example. This may be because the lithium-containing materials have good lithium ion conductivity, which reduces the resistivity of the electrode pieces.

[0059] As described above, the lithium-containing material according to the present invention can be used as an additive in lithium batteries to improve the rate characteristics of the batteries, extend the service life and cycle characteristics of the lithium batteries, significantly improve the safety performance of the lithium batteries, and allow the batteries to maintain good energy density.

[0060] The above-mentioned specific embodiments further describe the objectives, technical solutions and beneficial effects of the present invention, and the above are only specific embodiments of the present invention, and are not intended to limit the protection scope of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

[0061] (Addendum) (Appendix 1) A lithium-containing material comprising: The lithium-containing material is in the form of a white powder, and the components of the lithium-containing material include lithium (Li), aluminum (Al), phosphorus (P), fluorine (F), and oxygen (O), where, according to mass ratio, the content ratio of each element is as follows: the content of element lithium is more than 0% and not more than 12%, the content of element aluminum is 5% to 40%, the content of element phosphorus is 1% to 35%, the content of element fluorine is 0.4% to 22%, and the content of element oxygen is 2% to 34%; The lithium-containing material is used as an electrode additive or a diaphragm coating material for a lithium-ion battery. A lithium-containing material characterized by:

[0062] (Appendix 2) The X-ray diffraction (XRD) pattern of the lithium-containing material has characteristic diffraction peaks at 2θ angles of 28°, 30°, and 19°. 2. The lithium-containing material according to claim 1,

[0063] (Appendix 3) The tap density of the lithium-containing material is 0.60 to 1.48 g / cm 3 That is, 2. The lithium-containing material according to claim 1,

[0064] (Appendix 4) The solubility of the lithium-containing material in water, ethanol, N-methyl-2-pyrrolidone (NMP) is less than 1 g / 100 g; 2. The lithium-containing material according to claim 1,

[0065] (Appendix 5) The total content of magnetic impurities in the lithium-containing material is less than 1.5 ppm, and the magnetic impurities include one or more of Cr, Fe, Ni, Zn, and Co; 2. The lithium-containing material according to claim 1,

[0066] (Appendix 6) The lithium-containing material has a Cr content of ≦0.15 ppm, an Fe content of ≦1.35 ppm, an Ni content of ≦0.04 ppm, an Zn content of ≦0.01 ppm, and a Co content of ≦0.01 ppm. 6. The lithium-containing material according to claim 5,

[0067] (Appendix 7) The lithium-containing material is further doped with an element M, the content of the element M in the lithium-containing material is 0% to 30%, and the M is selected from any one of H, K, Cl, and Na. 2. The lithium-containing material according to claim 1,

[0068] (Appendix 8) The general chemical formula of the lithium-containing material is Li 1+xM 1-x Al(PO4)O 1-y F 2y where 0≦x≦1, 0 <y<0.1である、 8. The lithium-containing material according to claim 1 or 7,< / y<0.1である、

Claims

1. A lithium-containing material comprising: The lithium-containing material is in the form of a white powder, and the components of the lithium-containing material include lithium (Li), aluminum (Al), phosphorus (P), fluorine (F), and oxygen (O), where, according to mass ratio, the content ratio of each element is as follows: the content of element lithium is more than 0% and not more than 12%, the content of element aluminum is 5% to 40%, the content of element phosphorus is 1% to 35%, the content of element fluorine is 0.4% to 22%, and the content of element oxygen is 2% to 34%; The lithium-containing material is used as an electrode additive or a diaphragm coating material for a lithium-ion battery; The lithium-containing material is further doped with an element M, and the content of the element M in the lithium-containing material is more than 0% and not more than 30%, and the element M is selected from any of H, K, and Na; The general chemical formula of the lithium-containing material is Li 1+x M 1-x Al(PO 4 )O 1-y F 2y , where 0≦x≦1 and 0<y<0.1; The total content of magnetic impurities in the lithium-containing material is less than 1.5 ppm, and the magnetic impurities include one or more of Cr, Fe, Ni, Zn, and Co; A lithium-containing material characterized by:

2. The X-ray diffraction XRD pattern of the lithium-containing material has characteristic diffraction peaks at 2θ angles of 28°, 30°, and 19°.

2. The lithium-containing material of claim 1 .

3. The tap density of the lithium-containing material is 0.60 to 1.48 g / cm ３ That is, 2. The lithium-containing material of claim 1 .

4. The solubility of the lithium-containing material in water, ethanol, and N-methyl-2-pyrrolidone (NMP) is less than 1 g / 100 g.

2. The lithium-containing material of claim 1 .

5. the lithium-containing material has a Cr content of ≦0.15 ppm, an Fe content of ≦1.35 ppm, an Ni content of ≦0.04 ppm, an Zn content of ≦0.01 ppm, and a Co content of ≦0.01 ppm; 2. The lithium-containing material of claim 1 .

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